0 1988 The Pathological Society of Great Britain and Ireland Use of enzymes in typing group A p- haemolytic streptococci

Summary. A series of 698 strains of group A /?-haemolytic streptococci (GAS) isolated from children with streptococcal pyoderma was tested for production of serum opacity factor (OF) and nicotinamide adenine dinucleotide glycohydrolase (NADase). OF was produced by 37 % of strains and 40 % produced NADase. Classification based on various combinations of OF and NADase reactions showed that 58 % belonged to enzyme group el and 34 % to e2. Correlation with T and M types showed the possible use of this means of cldssification as an epidemiological marker for GAS. The specificity of such a system in the further classification of various T types of GAS in epidemiological studies, in the light of antigenic variation among M types, is described